1985 Mesa Studio .22

[g1]

Yeah, I'm not quite sure I understand either. The low volume sounds like an intermittent that has now cut out due to the chassis position/pressure on circuit board.
Howling is often due to tank positioning/hold down screw tension or one of the 2 reverb tubes being microphonic.

[ca7922303]

Yeah, I'm not quite sure I understand either. The low volume sounds like an intermittent that has now cut out due to the chassis position/pressure on circuit board.
Howling is often due to tank positioning/hold down screw tension or one of the 2 reverb tubes being microphonic.

I've changed all tubes to known good tubes, Reverb howl went away after resoldering some pot connections. Reverb was howling with Reverb control at any position, but amplifier volume control at '2' or greater caused issue. I'm going to run a signal thru input and try to trace where signal stops shortly. Will say that board is held in place with plastic fasteners which allows alot of flex it seems. Will post photos asap.

[ca7922303]

Photos of seven(7) plastic retainers holding board down.

[ca7922303]

So signal at input same as signal at speaker output. Checked over control pots again. Replaced bass pot, now all good. Ran it for about 2hiyrs with an mp3 signal and instrument. Thanks for the help.